====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.4.1070/8616 is trying to acquire lock: ffff0000cc078060 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x68/0x98 fs/pipe.c:91 but task is already holding lock: ffff0000c3048410 (sb_writers#5){.+.+}-{0:0}, at: do_splice+0x93c/0x1214 fs/splice.c:1348 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (sb_writers#5){.+.+}-{0:0}: percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs/super.h:19 [inline] sb_start_write+0x5c/0x294 include/linux/fs/super.h:125 mnt_want_write+0x44/0x9c fs/namespace.c:493 ovl_want_write+0x90/0xa0 fs/overlayfs/util.c:38 ovl_create_object+0xe4/0x340 fs/overlayfs/dir.c:706 ovl_create+0x38/0x48 fs/overlayfs/dir.c:737 lookup_open fs/namei.c:4511 [inline] open_last_lookups fs/namei.c:4611 [inline] path_openat+0x1244/0x2a6c fs/namei.c:4855 do_file_open+0x1c4/0x2e4 fs/namei.c:4887 do_sys_openat2+0x114/0x1e8 fs/open.c:1364 do_sys_open+0xac/0xdc fs/open.c:1370 __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __arm64_sys_openat+0x9c/0xb8 fs/open.c:1381 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #3 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}: down_read+0x58/0x2bc kernel/locking/rwsem.c:1568 inode_lock_shared include/linux/fs.h:1044 [inline] lookup_slow+0x4c/0x80 fs/namei.c:1931 walk_component fs/namei.c:2278 [inline] lookup_last fs/namei.c:2785 [inline] path_lookupat+0x324/0x774 fs/namei.c:2809 filename_lookup+0x1cc/0x3c0 fs/namei.c:2838 kern_path+0x4c/0x70 fs/namei.c:3044 lookup_bdev+0xc0/0x248 block/bdev.c:1213 resume_store+0x120/0x3e4 kernel/power/hibernate.c:1306 kobj_attr_store+0x6c/0x90 lib/kobject.c:840 sysfs_kf_write+0xe0/0x108 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x264/0x3c0 fs/kernfs/file.c:352 iter_file_splice_write+0x758/0xd3c fs/splice.c:736 do_splice_from fs/splice.c:936 [inline] direct_splice_actor+0xec/0x14c fs/splice.c:1159 splice_direct_to_actor+0x27c/0x744 fs/splice.c:1103 do_splice_direct_actor+0x140/0x228 fs/splice.c:1202 do_splice_direct+0x58/0x70 fs/splice.c:1228 do_sendfile+0x3e8/0x68c fs/read_write.c:1372 __do_sys_sendfile64 fs/read_write.c:1433 [inline] __se_sys_sendfile64 fs/read_write.c:1419 [inline] __arm64_sys_sendfile64+0x1b8/0x280 fs/read_write.c:1419 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #2 (&of->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x160/0xef8 kernel/locking/mutex.c:820 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:873 kernfs_seq_start+0x54/0x16c fs/kernfs/file.c:172 seq_read_iter+0x360/0xc04 fs/seq_file.c:226 kernfs_fop_read_iter+0x140/0x420 fs/kernfs/file.c:297 new_sync_read fs/read_write.c:493 [inline] vfs_read+0x4ac/0x8e4 fs/read_write.c:574 ksys_read+0x12c/0x224 fs/read_write.c:717 __do_sys_read fs/read_write.c:726 [inline] __se_sys_read fs/read_write.c:724 [inline] __arm64_sys_read+0x7c/0x90 fs/read_write.c:724 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x198/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #1 (&p->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x160/0xef8 kernel/locking/mutex.c:820 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:873 seq_read_iter+0xa8/0xc04 fs/seq_file.c:183 copy_splice_read+0x4b4/0x8d0 fs/splice.c:362 do_splice_read+0x1c4/0x2e0 fs/splice.c:980 splice_file_to_pipe+0x84/0xd4 fs/splice.c:1290 do_splice+0xcac/0x1214 fs/splice.c:1374 __do_splice fs/splice.c:1431 [inline] __do_sys_splice fs/splice.c:1634 [inline] __se_sys_splice fs/splice.c:1616 [inline] __arm64_sys_splice+0x2b4/0x4e0 fs/splice.c:1616 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #0 (&pipe->mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1780/0x2f44 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x368 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x160/0xef8 kernel/locking/mutex.c:820 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:873 pipe_lock+0x68/0x98 fs/pipe.c:91 iter_file_splice_write+0x188/0xd3c fs/splice.c:682 do_splice_from fs/splice.c:936 [inline] do_splice+0x9a0/0x1214 fs/splice.c:1349 __do_splice fs/splice.c:1431 [inline] __do_sys_splice fs/splice.c:1634 [inline] __se_sys_splice fs/splice.c:1616 [inline] __arm64_sys_splice+0x2b4/0x4e0 fs/splice.c:1616 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 other info that might help us debug this: Chain exists of: &pipe->mutex --> &ovl_i_mutex_dir_key[depth] --> sb_writers#5 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(sb_writers#5); lock(&ovl_i_mutex_dir_key[depth]); lock(sb_writers#5); lock(&pipe->mutex); *** DEADLOCK *** 1 lock held by syz.4.1070/8616: #0: ffff0000c3048410 (sb_writers#5){.+.+}-{0:0}, at: do_splice+0x93c/0x1214 fs/splice.c:1348 stack backtrace: CPU: 1 UID: 0 PID: 8616 Comm: syz.4.1070 Tainted: G L syzkaller #0 PREEMPT Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x328/0x330 kernel/locking/lockdep.c:2043 check_noncircular+0x158/0x174 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1780/0x2f44 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x368 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x160/0xef8 kernel/locking/mutex.c:820 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:873 pipe_lock+0x68/0x98 fs/pipe.c:91 iter_file_splice_write+0x188/0xd3c fs/splice.c:682 do_splice_from fs/splice.c:936 [inline] do_splice+0x9a0/0x1214 fs/splice.c:1349 __do_splice fs/splice.c:1431 [inline] __do_sys_splice fs/splice.c:1634 [inline] __se_sys_splice fs/splice.c:1616 [inline] __arm64_sys_splice+0x2b4/0x4e0 fs/splice.c:1616 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594